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GATE 2022 MT – Question 15

Physical Metallurgy · Materials characterization · 1 mark · Multiple choice

The sequence of peaks corresponding to the planes (in the order of increasing 2𝜃) observed in the X-ray diffractogram of a pure copper powder sample is __________

  1. 111, 200, 220, 311
  2. 110, 200, 211, 220
  3. 110, 200, 211, 311
  4. 111, 200, 311, 220

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Correct answer: (A) 111, 200, 220, 311

Explanation

Copper is FCC, allowing reflections whose indices are all odd or all even. Increasing h²+k²+l² gives 3,4,8,11, corresponding to **111,200,220,311, A**. Bragg angle increases with that squared-index sum.